I wanted to build a pack for my youngest son who is 6 years old. I decided to go with a spirit pack due to cost, size and weight. I showed him some reference photos of different packs and he decided he wanted a GB2 pack.

The most time consuming part of this effort was determining what I was going to change and how I would achieve it. I did this in many steps and changed my mind on some things, which made it take longer than it would have otherwise. Had I known what I know now, I would have approached this more systematically and it would have been more efficient. For example, removing all the portions of the pack that I would replace, at the same time; cutting all the PVC at the same time; cutting all the wood pieces at the same time, etc. I have no experience with projects like this so it was all trial and error.

I started by disassembling the pack; removed the cardboard backing, the stock electronics, lenses, straps, hoses, handles, etc. I removed all the stickers with goo-gone to end up with a bare shell.

THROWER:
The first thing I wanted to correct was the flimsy feeling of the thrower handles. It felt like a matter of time before they broke so I cut the grips out and cut out the handles entirely. I carefully saved the front handle pieces to use later.

I didn’t approach everything in the right order with the thrower. After cutting the grips out and sanding them to fit a 1/2” PVC tube, I used an acrylic orange paint on them. My plan was to paint, sand, paint sand multiple layers and then hit them with a clear coat to seal it.

I’ll also note that I tried a number of glues and epoxy’s and after using hot glue in some places, I replaced it with black milliput. That stuff isn’t too tacky, easy to mold and get hard as a rock once cured. For the PVC handles, I had to use a sanding drum to hollow them out a little to fit the clear tube.

Initially I used hot glue to secure the PVC handles but it wasn’t sturdy enough so I removed the hot glue and used JB weld, then reinforced it with milliput. Keeping the handles straight while the epoxy cured was difficult. When the handles are crooked, I think its very easy to spot so I was checking and rechecking when doing this.

The clear tube was cut from a saline flush (any paramedic out there will know what I’m talking about) and I wrapped it with masking tape and gently hit the exposed middle part with a sanding drum on the slowest setting. This gave it a frosted look.

The front handle parts were saved and glued with a two part epoxy and some fake welds were done with the milliput. I filled the weird gap spots with milliput and sanded them.

For the other two front rings, I simply cut them from the same PVC and sanded them to fit. I used Silver Rub N Buff to give them an aluminum finish. The trigger tip was cut from a piece of 1/8” basswood. I looked through reference photos of these, hand drew the shape on the wood and then cut it out. I put a notch in the PVC ring and glued it in place, then reinforced it with plumbers puddy epoxy. I used the Rub N Buff for the silver finish.

The banjo fittings were cut from a piece of plywood. I used the harder plywood instead of the basswood because of how small the pieces were and because I didn’t want them breaking easily. I drilled a hole in the bottom to accept a small brass tube. It gave a little detail to them. I painted gold and eventually finished them with antique gold Rub N Buff for a more authentic finish.

Originally I went with a 3D printed v hook but after a while it bugged me how big and wrong it looked so I made one from a sheet of aluminum.

The gun box had to be routed for the lights and switches so I cut the bottom out to create an access point. This made installing the electronics much easier. I utilized the existing screw holes to secure it. This piece would be attached to the gun track.

I ordered an 80% 3D printed gun track from Ben Of Kent and cut/shortened the back to make it sized right. On the gun track, I bought a simple ‘s’ hook and bent one side to create the hook. It was secured in place by 6-32 screws/nuts with washers.

For the three vent light openings, I drilled several holes and then used a file to shape the rest of the opening. I used this method for the bargraph hole as well.

I removed the existing molded ‘small knob’ on the right side and used a metal 1/8” shaft collar (cheap on eBay) to fit on the green lever I made from 1/8” metal rod (cheap at Home Depot). The green part was cut from the green tubing (purchased from gbfans.com)

I purchased spongeface’s spirit electronics so that had to be taken into account as I used the putty and such.

I corrected the top of the gun box to give it more of a rounded edge on the top left. I accomplished this by using a dremel sanding wheel, slowly sanding in the direction of the curve. I then use a sanding sponge to smooth it out. I also cut out the molded top knob. I placed a 1/2” nylon spacer (Home Depot) and fake welds for the top knob post. The top knob is 80% 3D printed and was ordered from Ben Of Kent.

For the screws i had to kinda wing it for some of the miscellaneous ones, like for the bottom plate and the tip trigger, but most of what I used for the build is 4-40, 6-32 or 8-32 screws. This made it easy when threading things like the front handle screws by the gun lock. For the brass spacers I found some 4mmx8mm brass bushings online. I think they’re used for RC cars or something.

The instrument bar was cut from a piece of square wood and routed for the lights. The rear cylinder was made with the existing molded piece glued and supported to a length of PVC that was partially cut to fit under the instrument bar. I tapped (8-32 I think) for the brass tube barbs (purchased on eBay). I had to use a couple long wood screws on the side to secure where the intensify button will go. I’m not at all happy with this move as it looks stupid but we’ll see, I may change it.

I filled the open space on the rear of the gun box with milliput, which held a couple 8-32 nuts in place. The long screws for instrument bar would thread into these, holding the instrument bar in place. In hindsight, i should have just tapped the milliput instead of using the nuts.

For the clippards I cut the knobs off, routed the inside and found some brass screws to give some weight and add some realism. I used epoxy to secure the screws.

The front knob on the gun box sat too low so I removed it, filled that hole with milliput and moved it closer to the top. I also used the silver Rub N Buff to give it a metallic finish.

For the loom, I ordered a 1/2” split less loom on amazon for about $8 and it fit perfectly after some light routing of the rear handle. This loom was far better proportioned than the stock one and much more flexible. I secured that in place with a long 6-32 screw that I tapped in place. To add some detail, I wrapped the loom in three spots with black electrical tape, similarly to the screen used packs.

After all this I sanded, primed and spray painted using an acrylic metallic paint, after covering the orange handles. I did a few layers to create some cool weathering when all done.

There were a few parts of the shell that clearly had to be fixed. The bumper/cyclotron area, the HGA (and space behind it), the area around the booster tube, the injectors and the right side of the pack - all had to be tweaked.

I used the dremel cutoff wheel to remove these areas and then sanded the edges straight and even. I used basswood for the replacement pieces. The curved spot near the vacuum line was done by cutting a segment of PVC from a 2” adapter. I used plumbers epoxy puddy to place most the wood pieces. Then filled the gaps with bondo and sanded it smooth.

The space behind the HGA was made by glueing /clamping multiple layers of the basswood together. Once the glue was set, I used a sanding drum to shape the top and right edge. I coated the sanded edge with JB weld and then sanded it smooth. I did this to avoid having the wood grain visible under the paint. Might not have been necessary.

I used an 8” aluminum cake pan for the cyclotron. I cut the holes using a step bit. I used bondo to keep it in place. If I were to do it again, I would use plumbers puddy epoxy. The gaps were filled with bondo applied over cardboard and then sanded. The rings were made from thin hobby wood. I got the 80% scaled lenses from Ben of Kent and used hot glue to place them. It was tricky getting the rings placed right and I found that the clear plastic lens piece that came with the spirit pack worked perfect for placement/spacing. I added two inward facing ‘dimples’ on each of the rings as well for added detail.

The HGA is PVC with two round cut pieces of wood, secured with an 8-32 screw. I drilled and tapped 6-32 screws for the four screws on the end. I initially used 10-24 screws on the end but they looked too big so I filled the holes and re tapped for the 6-32’s.

The molded crank knob was cut out and I patched the hole with milliput, then sanded smooth. I drilled a hole for a potentiometer that I had laying around to fit through. I purchased a set of molded 80% scaled resistors and an 80% scaled black crank knob was part of that set. The crank knob came in two pieces. I wanted it to function so I took one of the pins from the pack (used to hold the straps in), cut to length and fed it into holes drilled into the knob. When I cut it, it created a crimp in one end that prevents it from pulling through once fed up through the bottom. Perhaps not the best way to accomplish functionality for the knob but so far so good.

Since the ion arm is a very visible part, I ordered Ben’s 80% scaled aluminum ion arm end cap. I cut the end off the molded part and filled the hole with a piece of wood (2cm x 5.4cm) and glued it in place. This gave me a backing to screw the end cap to without making the whole thing stick out too far after cutting off the molded end cap. I removed the existing side ‘dale’ resistor as well as the other two molded resistors and filled/sanded the space flat. I replaced those with the scaled set I found on etsy. The larger resistor that the blue tube is connected to was hollowed out to allow the tube to pass through, which made securing it very easy. I placed one of the authentic brass Clippard pieces to the top where it receives the end of the same blue tube. A tiny touch brown paint to the inside edges on the resistors gave a nice weathered look.

The vacuum tube was an easy modification to make as it was simply a PVC adapter glued into place. The loom fed right in without issue and was glued in as well.

The beam line that was molded in the pack was cut out and the gap filled with bondo. I cut a length of 1/2” PVC and filled the ends to make the new one. I then drilled/tapped it and mounted it to the shell with an 8-32 screw.

For the loom that covers the blue wire (runs from filler elbow to HGA elbow), I went with a smaller 1/8” split loom. The stock one was too fat looking.

The shelf-like area around the EDA discs had to be shortened as it stuck way out. I cut the molded booster tube/booster frame out and sized the remaining portion properly. Then I built up the space where the booster tube was, using 1/4” plywood. The booster tube was cut to length and an angle cut made so it would sit properly. I created the top plug with a 1 1/2” piece of 1/2” PVC that was filled with bondo and then secured to a round cut piece of wood that was glued and wedged into the top of the tube. I then used hot glue (from the other end/opening of the booster tube) to glue it more so it wouldn’t shift. Once I found the right placement, I taped the shit out of it and drilled/tapped it from the back with 8-32 screws.

The booster frame was purchased as well from Ben of Kent (80% Scaled 3D Printed Booster Frame). The cable clamp was aged with the rest of the screws.

I aged the screws by placing them in a bowl with two cups of vinegar, one cup of water, 5 tablespoons of salt for 4 hours.. Then transferred them to another bowl with one cup of hydrogen peroxide and 5 tablespoons of salt for about 10 minutes.

I removed the PPD and cut the plastic loom part at the top. I used bondo to fill the hole this created and then drilled a clean hole that the blue tubing would feed into.

I bought two alkon straights on Etsy that I think worked out pretty good. They’re heavy but give some added realism to the overall look.

For the Injectors I cut two identical length PVC pieces. I hammered in some wood dowel pieces and then filled in the ends with bondo. I then tapped the top of each tube and glued them together down the middle. I used two rectangular pieces of wood to attach them to the shell at the top, secured then by two 2” 8-32 screws. Milliput at the bottom for the fake welds.

To prevent the injectors from getting snapped off, I used a small L bracket to connect them to the shell. I tapped the side of the injector to attach to the bracket and used an 8-32 screw and nut to secure the other side to the shell.

The spirit pack has a weird tube that the stock ribbon cable feeds in to that I cut off. I used the dremel to shape a clean hole for the ribbon cable.

The spectra-style ribbon cable was ordered on eBay. And I used a couple plastic cable ties to hold the twist. It’s not exactly GB2 accurate with the twist but I dig how it looks. I used a bigger cable tie to keep the end in the pack from coming out.

All of the Legris elbows and the Clippard brass fittings are real pieces that I purchased on eBay.

I ordered the 3D printed bumper from Ben of Kent. I gave him the measurements and he made a custom sized piece that worked great and only required a little shortening of the depth. I used 10-24 screws with brass 14s washers to secure it to the shell. The measurements that I sent him were:
“height of shell+cyclotron: 85mm.
width of the shell, where the bumper attaches: 27.2cm.”

The sexy looking bellows/shock mount was also purchased from Bed of Kent (“80% Scaled Metal Shock Mount”). I cut a nylon spacer to fit in the gap between the bumper and the cyclotron and painted that with the metallic silver spray paint. The shock mount/bellows is attached via one long carriage bolt from the inside of the shell , up through the bumper. I eventually replaced the metal shock mount with his 3D printed one to reduce the weight.

I made the N filter from a PVC adapter and the top round cap made from basswood. I bought some metal screen from a local hardware store for $2 that was cut and placed on the inside. Milliput was used for the fake welds here as well. 9 evenly spaced holes were drilled for this.

The two ‘bumps’ on the bottom of the shell were cut from hobby wood that I tapped and secured with 8-32 screws.

One of the noticeable characteristics of the shell, as it was when I bought it, was how sharp all the edges were. After looking over a million reference photos, I noticed how rounded the edges of the screen used shells were compared to the spirit pack. I used the dremel/sanding drum on the slowest setting to round pretty much every hard edge on the pack. I also roughed up the entire thing using the sanding sponges before moving on to the paint.

The motherboard was cut from MDF board. I found a shower drain at home depot that I cut to fit the speaker ring that came with the 3-way speaker. I found threaded 8-32 tubing pieces and secured them to some simple L brackets that I secured to the motherboard with rivets. If i did this again, I’d cut my own L brackets from an aluminum L bar and then drill/tap those.

I found sheets of 1/4” black foam at a local hobby shop that I cut to shape and glued to the top of the motherboard.

ALICE FRAME:
Since the pack itself is scaled down, I wanted an alice frame that was scaled to match. Since you can’t get a child size alice frame, I bought one to modify. I was lucky enough to find a decent frame from a local military surplus store and it had the correct GB2 belt.

I thought this part of the project would be a huge pain in the ass but it wasn’t at all. I got the whole frame done, start to finish, in a couple of hours.

I used a drill to remove the rivets and cut the frame to size. I cut a length of aluminum tubing to join the separated pieces at the top. I used JB weld to secure it and covered the separation with gaffers tape. I replaced the U bar that was on the frame with an aluminum U bar cut to fit. I made a V cut in the center to allow it to bend into a V. I cut a length of flat bar aluminum and secured that at the bottom of the frame. Everything was then joined together using steel rivets.

Afterwards, I hit the frame with a 2-in-1 primer/black paint. I found some pipe insulation foam at Home Depot that I used to make the neck padding. After cutting it to fit, I wrapped it with black gaffers tape.

ELECTRONICS:
I purchased the wand, light and sound kits from Spongeface (ghostlab42). I previously built a pack using Arduino and soldering LED’s to boards and decided it was well worth it to purchase his plug and play kit. He’s got pretty comprehensive instructions for these kits here:

PAINT:
I used grey primer for the pack and then taped off the areas that I didn’t want textured. I used an orange peel wall texture spray on the medium nozzle setting. The texture spray can get clumpy so before hitting the pack I carefully placed the whole can in a pot of hot water. I noticed as the can cooled, the spray became more clumpy. Once the texture coat was cured, I did some light sanding and then gave it another coat of primer.

I layered some of the parts and the thrower with a metallic chrome paint and sealed it with a couple coats of clear lacquer. This allowed for a good weathering effect later when I hit the black finish with steel wool.

I used a sanding drum (by hand) on ribbed parts of the pack, scraping the primer coat to create the wood grain effect.

I used a semi-gloss black for the finish. In hindsight I should have gone with either satin or flat black as the end result was far too wet/shiny looking and required a lot of dulling with steel wool to get the right look.

This was a fun project and my son is pretty stoked about it. I may add a n filter smoke kit eventually and if I do, I’ll try and update this. Thanks for looking!

I’m not familiar with the backpack mode but I assume besides the bag it’s pretty similar. As for the GB1 pack differences, the most glaring differences are the ribbon cable and crank knob. I’m doing my other sons spirit pack now as a GB1 pack and I’ll be sure to post progress on here as it gets moving.

Thanks for responding so quickly. Also, between the two movies did the ion arm change? I am new to prop building, and I have seen different model ion arms for sale and I would like to make sure I get the correct one.

The brass clippard elbow is square and located on the ion arm cap for the GB1. On the GB2 pack it’s hexagonal and located behind the ion cap on the arm itself. Several of the screws throughout the pack are different as well

I know it might be a rudimentary question, but I see that you're using the same battery that I have on my pack. With the integrated power switch on the battery, do you have to remove the motherboard each time you want to turn it on? Is there a way to install an external switch? Or do you just leave it on and haven't noticed any major draw?